Epithelial-like cells containing lymphocytes (nurse cells) in human adenoids and tonsils

Epithelial cells filled with lymphocytes (nurse cells, NC), recently described in mouse, rat and human thymus, have been interpreted as mediators of direct contact ('stromal') induced thymocyte maturation. We describe analogous NC in trypsin-dissociated human adenoids and tonsils. NC from these organs show morphological characteristics analogous to those of thymic NC: they appear as large (diameter 30-35 micrometers) elements, containing peripherally situated tonofilament bundles, electrodense mitochondria and some vacuoles. Each NC contains 5-30 intact lymphoid cells, some of which appear in the activated state. NC show neither phagocytic ability, nor ANAE and peroxidase cytochemical reactions. The majority of NC from adenoids and tonsils react with the monoclonal antibody (McAb) OKIa1 (DR w framework) as those from thymus, and 40% of them bind fluorescein-conjugated peanut agglutinin. Some of them also react with the McAb OKT3 (pan-T), OKT9 (transferrin receptors) and OKT10 (immature hematopoietic cells). The presence of NC in adenoids and tonsils suggests that these organs may be involved in some stages of lymphocyte maturation requiring intimate contact with epithelial cells.